Name two cell-organelles that are double membrane bound. What arethe
characteristics of these two organelles? State their functions anddraw labelled
diagrams of both.
Name two cell-organelles that are double membrane bound. What arethe
characteristics of these two organelles? State their functions anddraw labelled
diagrams of both.
Mitochondria and chloroplasts are the two organelles that aredouble-membrane-bound.
Characteristics of the mitochondria
Mitochondria are double- membrane-bound structures. The membraneof a mitochondrion is divided into the inner and outer membranes,distinctly divided into two aqueous compartments – outer andinner compartments. The outer membrane is very porous (containing theorganelle), while the inner membrane is deeply-folded.
These folds are known as cristae. Cristae increase the surfacearea inside the cell. They are the sites for ATP-generating chemicalreactions. The membrane of a mitochondrion contains specific enzymesmeant for specific mitochondrial functions. Hence, the mitochondriaare the sites for aerobic respiration. They have their own DNA andribosomes. Thus, they are able to make their own proteins. This iswhy they are considered as semi-autonomous organelles
Characteristics of chloroplasts
Chloroplasts are double-membrane-bound structures.
They are divided into outer and inner membranes, further dividedinto two distinct regions:
(i) Grana are stacks of flattened discs containingchlorophyll molecules. The flattened membranous sacs are calledthylakoids. The thylakoids of adjacent grana are connected bymembranous tubules called stroma lamellae.
(ii) Stroma is a homogenous mixture in which grana areembedded. It contains several enzymes that are used for the synthesisof carbohydrates and proteins. It also contains its own DNA andribosomes.
Functions of the mitochondria:
(i) They are the sites for cellular respiration.
(ii) They provide energy in the form of ATP for all vitalactivities of living cells.
(iii) They have their own DNA and ribosomes. Hence, theyare regarded as semi-autonomous organelles.
(iv) They have several enzymes, intermediately required forthe synthesis of various chemicals such as fatty acids, steroids, andamino acids.
Functions of chloroplasts:
(i) They trap solar energy and utilise it for manufacturingfood for plants. Hence, they are involved in the process ofphotosynthesis.
(ii) They contain the enzymes required for the synthesis ofcarbohydrates and proteins.
Mitochondria and chloroplasts are the two organelles that aredouble-membrane-bound.
Characteristics of the mitochondria
Mitochondria are double- membrane-bound structures. The membraneof a mitochondrion is divided into the inner and outer membranes,distinctly divided into two aqueous compartments – outer andinner compartments. The outer membrane is very porous (containing theorganelle), while the inner membrane is deeply-folded.
These folds are known as cristae. Cristae increase the surfacearea inside the cell. They are the sites for ATP-generating chemicalreactions. The membrane of a mitochondrion contains specific enzymesmeant for specific mitochondrial functions. Hence, the mitochondriaare the sites for aerobic respiration. They have their own DNA andribosomes. Thus, they are able to make their own proteins. This iswhy they are considered as semi-autonomous organelles
Characteristics of chloroplasts
Chloroplasts are double-membrane-bound structures.
They are divided into outer and inner membranes, further dividedinto two distinct regions:
(i) Grana are stacks of flattened discs containingchlorophyll molecules. The flattened membranous sacs are calledthylakoids. The thylakoids of adjacent grana are connected bymembranous tubules called stroma lamellae.
(ii) Stroma is a homogenous mixture in which grana areembedded. It contains several enzymes that are used for the synthesisof carbohydrates and proteins. It also contains its own DNA andribosomes.
Functions of the mitochondria:
(i) They are the sites for cellular respiration.
(ii) They provide energy in the form of ATP for all vitalactivities of living cells.
(iii) They have their own DNA and ribosomes. Hence, theyare regarded as semi-autonomous organelles.
(iv) They have several enzymes, intermediately required forthe synthesis of various chemicals such as fatty acids, steroids, andamino acids.
Functions of chloroplasts:
(i) They trap solar energy and utilise it for manufacturingfood for plants. Hence, they are involved in the process ofphotosynthesis.
(ii) They contain the enzymes required for the synthesis ofcarbohydrates and proteins.
